The invention relates to a device and a method for measuring at least one parameter of an extruded flat conductor cable in a water bath that follows the extruder.
Numerous devices are already known for measuring and determining cable parameters.
An optical determination of the outside diameter of the cable is possible, for example, or cables can be X-rayed to determine the distribution in transverse direction.
Furthermore known is a method of measuring the wall thickness of insulated strands and to use these data for adjusting the production process. For this, we refer to German reference 25 17 709. A device and a method for testing the wall thickness of an insulated layer is also disclosed in Swiss reference 667327 A5.
A different device for determining the position of a conductor relative to the outside surface of an extruded cable covering is known from reference EP-A 0 612 975.
These known devices use different measuring techniques for determining the desired parameters, wherein the wall thickness, for example, can be determined with the aid of an inductive measurement. However, a measuring technique of this type can be used only for determining the insulation wall thickness. In addition, this type of measurement strongly depends on the conductor dimensions, for example the width and thickness, wherein the sensor must furthermore be in contact with the cable.
The capacitive measuring technique, used multiple times in the past, can be compared to an inductive measuring. The conductors must be grounded for the capacitive measuring.
The ultrasonic technique as well has been used for determining diverse parameters, for example the wall thickness of plates and pipes. The same is true for the insulation of cables, provided they are round cables.
Nowadays, round cables are replaced more and more by flat conductor cables. In particular this applies to the automobile industry where flat conductor cables were produced until now primarily by laminating and/or gluing the insulating layer onto the flat conductors in the cable. However, such flat conductor cables are more and more produced with the aid of extrusion. In the process, problems occur which relate to the precise layout of the flat conductors in the cable, for example with respect to spacing and centricity.